1. Field of the Invention
The present invention relates to a heat transport device having an evaporator and a condenser and an electronic apparatus having the heat transport device. The present invention relates to heat transport technology that applies, for example, capillary pumped loops (CPL), which is a subject in the field of fluid micro-electro-mechanical systems (fluid MEMS). The heat transport device is suitable for reducing the size and thickness of the device and apparatus.
2. Description of the Related Art
For heat dissipation and cooling, typically, a heat pump is used. The heat pump has an air-tight container containing fluid. A wick, which is used for maintaining and refluxing the fluid, is installed inside the container. However, this type of heat pump has problems such as the following: it requires a large space; it is not suitable for downsizing; and its efficiency is reduced because fluid exists in both gas and liquid phases and, thus, the pipes bend. In addition, since the performance of this type of heat pump strongly depends on the distance and angle the fluid travels, the range of application for such a heat pump is restricted.
The recent development in technologies for electronic devices and micro-machines enable the production of even smaller devices. Among the technologies, the so-called MEMS technology, which applies a semi-conductor production process, has drawn attention. Research on applying the MEMS technology to heat transport devices has been carried out. The reasons for the research are the need for a heat source cooling system suitable for small and advanced electronic devices and the need for efficiently radiating heat generated by electronic devices, whose performance have recently dramatically improved.
In areas concerning MEMS, a structure utilizing capillary pumped loops (CPL) draws heat from a subject by undergoing repeated cycles of vaporizing a refrigerant at an evaporator and liquefying the evaporated refrigerant at a condenser (refer to Non-patent Document 1).
In a gas-liquid separation type heat pump having an evaporator and a condenser, heat is transported as described in the following.
(1) The fluid in a liquid phase transported from the condenser reaches the evaporator via a liquid phase channel and then is evaporated at the evaporator by receiving heat from the outside.
(2) The evaporated fluid moves, at high speed, through the vapor phase channel towards the condenser. Then the evaporated fluid returns to liquid by releasing heat to the outside at the condenser.
(3) The heat transport sequence described in (1) and (2) is repeated inside sealed piping.
[Non-Patent Document 1]
Jeffrey Kirshberg, Dorian Liepmann, Kirk L. Yerkes, “Micro-Cooler for Chip-Level Temperature Control,” Aerospace Power Systems Conference Proceedings, (USA), Society of Automotive Engineers, Inc., Apr. 1999, P-341, pp. 233–238.